218704 Testing the Effectiveness of a Small Group Substance Use Prevention Component Using Propensity Score Matching

Tuesday, November 9, 2010

Stephanie Ayers, PhD , Southwest Interdisciplinary Research Center, Arizona State University, Phoenix, AZ
Flavio Francisco Marsiglia, PhD , School of Social Work, Arizona State University, Phoenix, AZ
Stephen S. Kulis, PhD , Sociology, AZ State University, Phoenix, AZ
Because the keepin' it REAL model prevention program takes place in regular classrooms, teachers are often faced with delivering curriculum to students with a wide array of substance use risk behaviors. Due to this, a small group component, REAL Groups, was developed to enhance the effectiveness of keepin' it REAL for the most at-risk students. A total of 109 7th grade students were referred to and participated in REAL Groups. The remaining 252 7th grade students who did not participate served as the basis for the control group. To account for biased selection into REAL Groups, propensity score matching (PSM) was employed. Once propensity scores were obtained, balance achieved, and common support attained, nearest neighbor matching without replacement was used to match students from the treatment group to the control group. Once matched, the final sample size was 108: 54 from the treatment group and 54 from the control group. The estimated average treatment effect on the treated for alcohol use at the end of 8th grade was calculated. Results indicated that alcohol use decreased among students who participated in the REAL Groups relative to matched students who did not participate (ATT=-.166; p=.05). By using PSM this study accounted for problems that arise in non-experimental designs with non-equivalent comparison groups. Using PSM allowed the researchers to create two groups, treatment and control, which were not statistically different from each other. This allowed for a less biased effect of participating in the REAL Groups, which showed that participation decreased alcohol use.

Learning Areas:
Diversity and culture
Social and behavioral sciences

Learning Objectives:
Learning objectives: 1.Describe Propensity Score Matching 2.Discuss the effectiveness of using Propensity Score Matching in samples with selection bias. 3.Assess the effectiveness of REAL Groups, a small group component for keepiní it REAL, on alcohol use.

Keywords: Alcohol Use, Latinos

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am qualified to present because I ran all of the analyses and wrote the methods and findings.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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